/**
* This method implements weights update procedure for the single neuron
*
* @param neuron neuron to update weights
*/
@Override
protected void updateNeuronWeights(Neuron neuron) {
double output = neuron.getOutput();
for (Connection connection : neuron.getInputConnections()) {
double input = connection.getInput();
double weight = connection.getWeight().getValue();
double deltaWeight = (input - output * weight) * output * this.learningRate;
connection.getWeight().inc(deltaWeight);
}
}
// get unit with closetst weight vector
private Neuron getClosest() {
// Iterator<Neuron> i = this.neuralNetwork.getLayerAt(1)
// .getNeuronsIterator();
Neuron winner = new Neuron();
double minOutput = 100;
for (Neuron n : this.neuralNetwork.getLayerAt(1).getNeurons()) {
// while (i.hasNext()) {
// Neuron n = i.next();
double out = n.getOutput();
if (out < minOutput) {
minOutput = out;
winner = n;
} // if
} // while
return winner;
}
/**
* This method implements weights update procedure for the single neuron
*
* @param neuron neuron to update weights desiredOutput desired output of the neuron
*/
protected void updateNeuronWeights(Neuron neuron, double desiredOutput) {
for (Connection connection : neuron.getInputConnections()) {
double input = connection.getInput();
double deltaWeight = input * desiredOutput * this.learningRate;
connection.getWeight().inc(deltaWeight);
}
}
@Before
public void setUp() {
instance = new Max();
inputNeurons = new ArrayList<>(4);
for (int i = 0; i < 4; i++) inputNeurons.add(new InputNeuron());
Neuron toNeuron = new Neuron();
toNeuron.setInputFunction(instance);
inputConnections = new ArrayList(4);
for (int i = 0; i < 4; i++) {
Connection inConn = new Connection(inputNeurons.get(i), toNeuron, 1);
inputConnections.add(inConn);
toNeuron.addInputConnection(inConn);
}
}
private void adjustCellWeights(Neuron cell, int r) {
// Iterator<Connection> i = cell.getInputsIterator();
// while (i.hasNext()) {
// Connection conn = i.next();
for (Connection conn : cell.getInputConnections()) {
double dWeight = (learningRate / (r + 1)) * (conn.getInput() - conn.getWeight().getValue());
conn.getWeight().inc(dWeight);
} // while
}
private void learnPattern(DataSetRow dataSetRow, int neighborhood) {
neuralNetwork.setInput(dataSetRow.getInput());
neuralNetwork.calculate();
Neuron winner = getClosest();
if (winner.getOutput() == 0) return; // ako je vec istrenirana jedna celija, izadji
Layer mapLayer = neuralNetwork.getLayerAt(1);
int winnerIdx = mapLayer.indexOf(winner);
adjustCellWeights(winner, 0);
int cellNum = mapLayer.getNeuronsCount();
for (int p = 0; p < cellNum; p++) {
if (p == winnerIdx) continue;
if (isNeighbor(winnerIdx, p, neighborhood)) {
Neuron cell = mapLayer.getNeuronAt(p);
adjustCellWeights(cell, 1);
} // if
} // for
}
/**
* Calculates predict values for every possible class that instance can be classified as that
*
* @param instnc Instance
* @return Map<Object, Double>
*/
@Override
public Map<Object, Double> classDistribution(Instance instnc) {
// Convert instance to double array
double[] item = convertInstanceToDoubleArray(instnc);
// set neural network input
neuralNet.setInput(item);
// calculate neural network output
neuralNet.calculate();
// find neuron with highest output
Map<Object, Double> possibilities = new HashMap<Object, Double>();
for (Neuron neuron : neuralNet.getOutputNeurons()) {
possibilities.put(neuron.getLabel(), neuron.getOutput());
}
return possibilities;
}
/**
* Classifies instance as one of possible classes
*
* @param instnc Instance to classify
* @return Object class as Object
*/
@Override
public Object classify(Instance instnc) {
double[] item = convertInstanceToDoubleArray(instnc);
// set neural network input
neuralNet.setInput(item);
// calculate neural network output
neuralNet.calculate();
// find neuron with highest output
Neuron maxNeuron = null;
double maxOut = Double.NEGATIVE_INFINITY;
for (Neuron neuron : neuralNet.getOutputNeurons()) {
if (neuron.getOutput() > maxOut) {
maxNeuron = neuron;
maxOut = neuron.getOutput();
}
}
// and return its label
return maxNeuron.getLabel();
}
